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From:   Sasha Levin <Alexander.Levin@microsoft.com>
To:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "stable@vger.kernel.org" <stable@vger.kernel.org>
CC:     Minwoo Im <minwoo.im.dev@gmail.com>,
        Christoph Hellwig <hch@lst.de>,
        "Sasha Levin" <Alexander.Levin@microsoft.com>
Subject: [PATCH AUTOSEL for 4.14 021/100] nvme-pci: avoid hmb desc array idx
 out-of-bound when hmmaxd set.
Thread-Topic: [PATCH AUTOSEL for 4.14 021/100] nvme-pci: avoid hmb desc array
 idx out-of-bound when hmmaxd set.
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Date:   Wed, 24 Jan 2018 04:14:33 +0000
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From: Minwoo Im <minwoo.im.dev@gmail.com>

[ Upstream commit 244a8fe40a09c218622eb9927b9090b0a9b73a1a ]

hmb descriptor idx out-of-bound occurs in case of below conditions.
preferred =3D 128MiB
chunk_size =3D 4MiB
hmmaxd =3D 1

Current code will not allow rmmod which will free hmb descriptors
to be done successfully in above case.

"descs[i]" will be set in for-loop without seeing any conditions
related to "max_entries" after a single "descs" was allocated by
(max_entries =3D 1) in this case.

Added a condition into for-loop to check index of descriptors.

Fixes: 044a9df1("nvme-pci: implement the HMB entry number and size limitati=
ons")
Signed-off-by: Minwoo Im <minwoo.im.dev@gmail.com>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
 drivers/nvme/host/pci.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 66d872b05024..5dae650438c1 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -1645,7 +1645,7 @@ static int __nvme_alloc_host_mem(struct nvme_dev *dev=
, u64 preferred,
 	if (!bufs)
 		goto out_free_descs;
=20
-	for (size =3D 0; size < preferred; size +=3D len) {
+	for (size =3D 0; size < preferred && i < max_entries; size +=3D len) {
 		dma_addr_t dma_addr;
=20
 		len =3D min_t(u64, chunk_size, preferred - size);
--=20
2.11.0